The development of explosives has been important in the history of civilization. The earliest explosives were deflagrating, beginning with black powder. Roger Bacon, in the thirteenth century, detailed the preparation of black powder. It was originally used in firearms, and not until the seventeenth century was it used in mines.
Detonating explosives were developed in the nineteenth century, based on the work of Alfred Nobel. Mr. Nobel succeeded in mixing nitroglycerin with an absorbent instead of a liquid which was difficult to handle and dangerous to transport. A solid substance, dynamite, was developed that was sensitive to the action of a blasting cap, but was relatively insensitive to ordinary shock.
Since the development of detonating explosives, continuing effort has been directed to maximize both the explosive force and the safety of explosive compositions and processes. Ammonium nitrate-fuel oil compositions have been effective explosives and safe to transport, but exhibited relatively modest detonating energy.
A wide variety of high energy reactions has been explored to discover means for generating a high heat of reaction and explosive energy. The known thermite reaction, in which iron oxide is reacted with aluminum to form iron and aluminum oxide, can generate a heat of reaction of about 0.94 kcal per gram and will reach a temperature of about 2200° C. In addition, it has been recognized that chemical compounds that are exposed to high temperatures will rapidly decompose. It has also been recognized that the reaction of polytetrafluoroethylene with aluminum under pressure generates about 3.16 kcal per gram.
Despite a wide variety of known high energy reactions, including those noted above, continued effort has been directed toward the development of explosive processes that will yield exceptional energy.